Experimental calibra/on of the ARA radio neutrino ... · 14th, July, 2017, ICRC2017 The ARA calibraon with the TA-ELS (ARAcalTA) Performed in January, 2015 at TA site, Utah Purpose:

14th,July,2017,ICRC2017

Experimentalcalibra/onoftheARAradioneutrinotelescopewithanelectronbeaminice

R.Gaior,A.Ishihara,T.Kuwabara,K.Mase,M.Relich,S.Ueyama,S.YoshidafortheARAcollaboraFon,

M.Fukushima,D.Ikeda,J.N.MaLhews,H.Sagawa,T.Shibata,B.K.ShinandG.B.Thomson

K.Mase 1


■ TheARAcalibra/onwiththeTA-ELS(ARAcalTA)PerformedinJanuary,2015atTAsite,Utah�

Purpose:BeLerunderstandingoftheradioemissionsandthedetectorcalibraFon �

Wemeasured²  PolarizaFon²  AngulardistribuFon²  Coherence

Antenna tower Extendable: 2-12m�

Ice target�

Vpol antenna�Hpol antenna�

40 MeV electron beam line�

TA LINAC �

Bicone ARA antenna

150-850 MHz� LNA + filter (230-430 MHz)�

K.Mase 2

�


■ TALINACMeasured bunch structure ~10 bunches�

2 ns�

2×108 electrons → Enough signal strength

Correlation → Monitor of electron number�

Cover wide range → Coherence�

ü  40MeVelectronbeamü  Typicalelectronnumberperbunchtrain:2×108

→30PeVEMshowerü  Pulsefrequency:2.86GHz

→pulseinterval:350ps

ü  BunchtrainwidthwasopFmizedto~2nsü  Beamlateralspread:~4.5cmü  Triggersignalavailableü  Electronnumbercanbemonitored(~3%)

K.Mase 3

■ Icetargetandtheconfigura/onsl  100 x 30 x 30 cm3 l  Easily rotatable structure

l  Easily movable on a rail

l  Plastic holder for the ice has a hole underneath for the beam

40 MeV electron beam line�

l  Main data sets l  With ice (30°, 45°, 60°) l  No target�

Thermometer �

Dry ice (on side) �1 m�

α=60°�

α=30°�

Cherenkov angle in ice (56°)�

R. Gaior, 1135, ICRC2015 �


observation angle�

40MeVelectrons�

emission angle�

emission angle [deg.]�

ice inclination angle (α)

Ice target�

K.Mase 4

Electrons stop after running 20 cm in ice due to an ionization loss → Wide angle distribution


■ Expectedradioemissionsü  Several radio emissions are expected

ü  Askaryan radiation ü  In ice ü  Wide angular distribution due to the short tracks ü  Peak at more horizontal direction than the

Cherenkov angle (56°)

ü  Transition radiation ü  At air/ice boundary ü  Peak at Cherenkov angle (56°)

ü  Sudden appearance radiation ü  When beam appears ü  Forward emission (Cherenkov angle is ~1°) ü  More in Krijn’s talk on Tuesday

ElectronLightSourcefacility�

20 cm hole�

metal �

ice �

beam pipe�

40MeVelectrons�

Askaryan radiation�

Transition radiation�

Sudden appearance signal�

K.Mase 5

Obs. angle 0° (no target) at 1 m�

Middle point

Endpoints

14th,July,2017,ICRC2017K.Mase 6

■ Simula/on �Bunch structure �

2 ns�

Lateral distribution�

4.5 cm�

ElectronLightSourcefacility�

20 cm hole�

metal �

ice �

beam pipe�

40MeVelectrons�

Emission in ice�

Emission in air�

Electron beam (Geant4)�

E-field calculation�

Ray trace �

Based on the classical EM theory (Lienard-Wiechert potentials)

Middle point method (PRD 81, 123009 (2010))

Endpoints method (PRE84, 056602 (2011))

Thanks to Anne Zilles for sharing her code for the implementation

Including accelerator configurations�

E-field �

tables made�

20 cm�

E-fi

eld

[V/m

]�

14th,July,2017,ICRC2017 �

■ Detectorsimula/on

＋� ＋�

=�

E-field � Antenna response (T-domain)� filter + LNA response�

K.Mase� 7�

2 ns�

R. Gaior, 1135, ICRC2015�

Time [ns]� Time [ns] � Frequency [GHz]�

E-fi

eld

[V/m

]�

Ant

enna

hei

ght [

m]�

Gai

n [d

B]�

Time [s]�

Volta

ge [V

]�

5 ns� 230-430 MHz�

Verify the understanding the emission mechanisms and detector responses, comparing with data�

Obs. angle 0° (no target) at 1 m�

Time [ns]40 60 80 100 120 140

Volta

ge [V

]

-0.3

-0.2

-0.1

0

0.1

0.2

0.3Time [ns]

40 60 80 100 120 140

Volta

ge [V

]

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

■ Comparisonsofwaveformandthefrequencyspectrum

ü  Reasonable agreements between data and simulation after correcting the cable attenuation

ü  Less Hpol signal → high polarization

ü  Some indications of noise

Vpol �

Hpol �

Vpol �

Configuration: Ice 60°, obs. angle: 15°

Simulation Data �

Simulation Data �

Simulation Data


Groupreview� 9�

■ Cable/connectoraYenua/oncorrec/onFaraday Cup (for the electron charge measurement)�

TA short cables / connectors (~3m, up to 500 MHz)� Long cables (40m, high

frequency adapted)�

TA LINAC �

oscilloscope�

Counting house�40MeVelectrons�

K.Mase�

Long (45 m)

Short (3 m) Short + Long (40 m)�

Original Long (45 m)

Short (3 m)

Short + Long (40 m)�

Charge loss 9.9 %

23.5%

45.7%�

²  Found out the TA short cable attenuate signal significantly ²  Electron number for data was underestimated by 46% ²  The emission power is proportional to the charge square → correction of x2.1 (1.462) ²  Original bunch structure turned out to be more narrower

Time [ns]�

Volta

ge [V

]�

Time [ns]40 60 80 100 120 140

Voltag

e [V]

-0.3

-0.2

-0.1

0

0.1

0.2

0.3 Data Simulation�

Time [ns]�

■ Polariza/onPolarization�

Polarization angle�

Data (Ice target) Simulation (Ice target) Data (No target)�

ü  All signals shows relatively high vertical polarization

ü  Smaller polarization for the no target configuration ü  Less polarized signals for the outside of the main

peak → indication of the noise contamination

Icetarget 0.92±0.03

SimulaFon 1.00±0.01

Notarget 0.82±0.03

Highly polarized�

Configuration: Ice 60°, obs. angle 15°, Vpol�Time development of polarization�

Pol

ariz

atio

n�Time [ns]�

Data Simulation�


Volta

ge [V

]�

(electron number)10

Log7.6 7.8 8 8.2 8.4 8.6

(radi

o en

ergy

[J])

10Lo

g

-11.8

-11.6

-11.4

-11.2

-11

-10.8

-10.6

-10.4

-10.2

Time [ns]0 20 40 60 80 100 120 140 160 180 200

Voltag

e [V]

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

Data Simulation�

Volta

ge [V

]�

Time [ns]�


■ Coherence

Slope index: 1.86 ± 0.01�

ü  High coherence, but not full → Possibly due to the noise

ü  Similar values for all the configurations (Even Hpol too)�

Data

ü  High coherence around the all main pulse ü  Noises seem to show the high coherence�

Configuration: Ice 30°, obs. angle 0°, Vpol�Time development of coherence�

Time [ns]�

Slo

pe in

dex�

K.Mase 11


■ Angulardistribu/on

ü  Noise were filtered using a time window (±5 ns) with respect to the peak in a waveform

ü  Reasonable agreement after applying the noise cut (otherwise the shapes do not agree, data is ~60% higher)�

ElectronLightSource

facility�

ice �

40MeVelectrons�

Observation angle�

Preliminary�

distance corrected, but antenna gain not corrected�

K.Mase 12

θc(30°)� θc(45°)� θc(60°)�


■ Summaryl  We have performed an experiment at Utah using the TA-ELS for the better

understanding of radio emissions and the ARA antennas

l  Highly polarized and coherent signals were observed

l  Radio signals observed from the beam appearance

l  More signals observed when using an ice block

l  Agreements improved after correcting the cable attenuation

l  More detail simulation constructed to take the reflection and refraction into account

l  Need to understand the noise a little better

l  Like to understand how much Askaryan signals are contained using simulation

K.Mase 13


Backups �

K.Mase 14


2km

²  Aimstodetecthighenergyneutrinosabove30PeVusingAskaryanradiaFon

²  37staFons(3staFonsdeployedsofar)²  EachstaFonhas4stringsat200mdepth²  Eachstringhas2Vpol+2Hpolbroadband

antennas(~200–800MHz)

²  Totalsurfacearea~100km2

²  ~10IceCube@1EeV�

Astroparticle Physics 35 (2012) 457–477�

■ AskaryanRadioArray(ARA)

K.Mase 15

GroupreviewK.Mase 16

[dBi]�

Angle [deg.]�

Bunch number�

Rat

io�

■ Systema/cuncertain/es

Bunch after cable correction Widest case

Shortest case �

1 ns�

Original Long (45 m)

Short (3 m)

Short + Long (40 m)�

Item Data Simula/on

StaFsFcalerror ±7% ±10%

Stability ±19% -

Antennaresponseuncertainty

-17%+14%

Bunchwidth - -14%+17%

Sum ±20% ±24%

Time [ns]�

1 ns�

17/07/14� 17�

■ Waveformagreements(notarget)

0 m� 3.5 m�

7.4 m�ü  Timing is matched with a cross correlation ü  Time difference between data and simulation

is explained by cable delay etc. ü  Agreements are reasonable

ü  Prepulse seen �

Data Simulation�

Δt = 137.5 ns Δt = 138.9 ns

Δt = 139.7 ns

17/07/14� 18�

■ Residual signal (notarget)0 m� 3.5 m�

7.4 m�ü  Similar shape ü  Similar amplitude

ü  Time correlates with signal

→ generated at source? Prior to the signal? ü  10 ns earlier (3 m below the cover box)

ü  From the end of the beam pipe?

ü  No distance dependence?

Data - Simulation�

17/07/14� 19�

■ Spectrumagreements(notarget)

0 m� 3.5 m�

7.4 m�ü  Similar behaviors ü  Difference becomes larger at high height

because the signal is weaker and the effect of additional component is larger�

Data Simulation�

17/07/14� 20�

■ Residual spectrum (notarget)0 m� 3.5 m�

7.4 m�ü  Quite similar shape ü  Flat spectrum →�White noise?�

14th, July, 2017, ICRC2017

■ TheARAsensi/vity

ARA37 (3yr)�

ARA Test Bed limit�

ARA2 limit�

K.Mase 21


■ Reproducibility

Vpol � Hpol �

The reproducibility was checked with data with the same configuration

2015/01/14 Run1 (ice 60 deg., 0m)

2015/01/14 Run4 (ice 60 deg., 0m)�

The difference in the amplitude is 5% → 10% in power (Vol) �

K.Mase� 22�


■  Stability and far field confirmation ü  Thestabilitywiththesame

configuraFon:5%inamplitude

ü  TheantennamastwasintenFonallyrotatedby~15deg.

ü  ThesignalamplitudedecreasedproporFonallywiththedistancechange.→FarfieldconfirmaFon(3.0nsFmedelay→11%distant→12%amplitudedecrease)

ü  TimedifferencefromtheexpectaFonwascheckedforeachconfiguraFon.

ü  Thespreadis1.9ns→9°rotaFon→6%inamplitude

ü  TheoverallsystemaFcuncertaintyinpower:16%

15 degrees�

2015/01/14 Run1 2015/01/14 Run3 (3.0 ns delay corrected)

Configuration: Ice 60°, obs. angle: 0°, Vpol

K.Mase� 23�

14th, July, 2017, ICRC2017

■ TheARAsystem

DAQ box�

optical fiber (~200 m)�

DAQ at surface �

LNA�

in-ice �

~40 dB�

band-pass filter �

Antennas�

calibrate these detectors�

V-pol antenna Bicone

150-850 MHz

�

H-pol antenna Quad-slot cylinder

200-850 MHz

Gain similar to dipole (+2 dBi)

�

~40 dB�

K.Mase 24

14th, July, 2017, ICRC2017

■ Schema/coftheARAsystem

DAQ box�FOAM �DTM�

optical fiber signal transfer system�

Antenna�

optical fiber (200m)�

band-pass filter �

DAQ at surface �LNA� DTM� FOAM �

in-ice �

~40 dB�

K.Mase 25


■ Antennas

V-pol antenna Bicone

150-850 MHz

�

H-pol antenna Quad-slot cylinder

200-850 MHz

Gain similar to dipole (+2 dBi)

�

K.Mase 26

Documents

Experimental calibra/on of the ARA radio neutrino ... · 14th, July, 2017, ICRC2017 The ARA calibraon with the TA-ELS (ARAcalTA) Performed in January, 2015 at TA site, Utah Purpose: